fig5
![Automated machine learning structure-composition-property relationships of perovskite materials for energy conversion and storage](https://image.oaes.cc/6aa7188a-b9f8-42c8-a44c-e3fd2d0b0525/4352.fig.5.jpg)
Figure 5. The process of descriptor construction by extreme feature engineering. The xi (i = 1, 2, … n) indicates the chosen feature. The parameters following the arrows denote the constructed a large number of brand-new descriptors. These 9 functions of x, x-1, , x2, x3, ex, ln|x|, ln(1 + |x|) and log|x| are employed in the nonlinear conversion of features. All of the descriptors mixed in a nonlinear way to construct more descriptors.